I may be missing something here, by knowing nothing about lubricating oil.
Gallons are volume, so can be converted directly to cubic feet ... even if they're empty.
There doesn't need to be a substance involved, and if there is, its weight is irrelevant.
42 US gallons ===> 5.6146 cubic feet (rounded)
A barrel of oil contains 42 gallons. A gallon of light crude oil weighs approximately 7.27 pounds. Heavy crude oil weighs 7.61 pounds per gallon. Therefore a barrel of light crude oil weighs 305.34 pounds + the weight of the barrel. Heavy crude would weigh 319.62 pounds + the weight of the barrel.
Approximately 6.073 pounds per US gallon.
1 US gallon of water is approximately 8.35 pounds. -1 Imperial gallon is approximately 10 pounds.
Approximately 6.5 pounds
46
There are no gallons in ounces. However one Imp gallon weighs approximately 10 pounds or 160 ounces. One USG is approximately 8.35 pounds.
That is approximately 7.986 pounds
Approximately 8.3 pounds.
One US gallon of gasoline is approximately 6.3 pounds
Approximately 458 pounds.
A US gallon of gasoline weighs approximately 6.3 pounds.
There is approximately 8.3454 pounds per gallon. Therefore 5 gallons is approximately 41.727 pounds.